exercise/src/main/java/com/code/stream/helloworld/BatchWordCount.java
<reponame>liushengxi13689209566/flink-study<filename>exercise/src/main/java/com/code/stream/helloworld/BatchWordCount.javapackage com.code.stream.helloworld;

import org.apache.flink.api.common.functions.FlatMapFunction;
import org.apache.flink.api.common.typeinfo.Types;
import org.apache.flink.api.java.ExecutionEnvironment;
import org.apache.flink.api.java.operators.AggregateOperator;
import org.apache.flink.api.java.operators.DataSource;
import org.apache.flink.api.java.operators.FlatMapOperator;
import org.apache.flink.api.java.operators.UnsortedGrouping;
import org.apache.flink.api.java.tuple.Tuple2;
import org.apache.flink.util.Collector;

public class BatchWordCount {
    public static void main(String[] args) throws Exception {
        //1. 获取Flink批处理执行环境
        ExecutionEnvironment env = ExecutionEnvironment.getExecutionEnvironment();
        // 获取文件中内容
        DataSource<String> dataSource = env.readTextFile("src/main/data/input.txt");

        // 对数据进行处理
        FlatMapOperator<String, Tuple2<String, Long>> wordAndOneTuple = dataSource.flatMap(new FlatMapFunction<String, Tuple2<String, Long>>() {
            @Override
            public void flatMap(String line, Collector<Tuple2<String, Long>> out) {
                String[] words = line.split(" ");
                for (String word : words) {
                    out.collect(Tuple2.of(word, 1L));
                }
            }
        }).returns(Types.TUPLE(Types.STRING, Types.LONG));

        //  按照 word 分组
        UnsortedGrouping<Tuple2<String, Long>> wordAndOneGroup = wordAndOneTuple.groupBy(0);

        //分组内聚合
        AggregateOperator<Tuple2<String, Long>> res = wordAndOneGroup.sum(1);

        res.print();

    }
}
